Making cast mill rolls



March 28, 1950 Filed Dec. 29, 1945 F. CORDES MAKING CAST MILL ROLLS 2Sheets-Sheet l INVENTOR Frank (O/04. 5

March 28, 1950 CQRDES MAKING CAST MILL ROLLS 2 Sheets-Sheet 2 Filed Dec.29, 1945 INVENTOR Frank Coraes Patented Mar. 28, 1,950

UNlTED STATES PATENT OFFICE MAKING CAST MILL ROLLS Frank Cordes,Pittsburgh, Pa.

Application December 29, 1945, Serial No. 637,845

2 Claims.

This invention relates to the manufacture of cast rolls, e. g., steel oriron rolls such as those used in rolling mills and, in particular, torolls having a body including a plurality of cylindrical portions ofvarious diameters.

The casting of high-quality mill rolls involves the exercise of a gooddeal of skill and experience in order to produce rolls which are toughand sound and have surfaces highly resistant to wear during use.

The demands of the rolling-mill art-are such that the roll maker isoftentimes called upon to produce a cast rollwhose body is of differentdiameters at difierent points along its length, as distinguished fromthe plain cylindrical roll body or barrel of uniform diameter from endto end. In making a roll with a body of varying diameter, it should becast to a form approximating the desired configuration, that is to say,the roll as cast should ideally be of such configuration that thefinishing of the cast roll in the roll lathe involves the removal ofsubstantially the same thickness of metal from all of the surfaces, inthe body portion, at least, of the casting.

The casting of such a roll body by present methods is not whollysatisfactory. The resulting roll may not be uniform in its physicalcharacteristics, or may be otherwise of less than top qualitymetallurgically. Difficulties in moldin and casting are alsoencountered. Despite the existence of these shortcomings over a longspan of years, the molding process has remained substantially unchanged.

My invention eliminates these difllculties and results in a cast roll ofsuperior physical properties. My invention is also advantageous in thatthe manufacture of the rolls is simplified in many respects and thepercentage of sound and satis factory castings is increased.

A complete understanding or the invention may be obtained from thefollowing detailed description, referring to the accompanying drawingswhich illustrate somewhat diagrammatically a flask for use in castingrolls in accordance with my invention. In the drawings,

Figure l is a central vertical section through one form of mold forpracticing the invention;

Figure 2 is a similar view of a modification.

Referring in detail to the drawings, I provide a flask ID for a sandmold having a cavity II corresponding in shape to the roll which it isdesired to cast. It will be understood that the cavity is somewhatlarger in all dimensions than shown at Ila in dot-and-dash lines,providing a substantially uniform thickness of surface material to beremoved in the finishing operation. As shownin the drawings, the rollIla to be cast in the cavity l I includes, in addition to the usualnecks l2, spaced cylindrical body portions of vari-. ous diameters,-i.e., collar portions I3, I 4 and lb of one diameter and intermediate bodyportions or grooves l6 and ll of a smaller diameter.

The flask I0 comprises a plurality of superposed wall portions orsections of different diameters. A cylinder l8 resting on a base l9 hasupper and lower flanges. The inside diameter of the cylinder 18 exceedsthat of the portion of the cavity ll forming the lower neck 12 by apredetermined amount. A second cylinder 20 having upper and lowerflanges rests on the upper flange of the cylinder I8 and is disposedcoaxially therewith. The inside diameter of the cylinder it exceeds thediameter of the body portion l5 by the same predetermined amountaforementioned. A flanged cylinder 2! resting on the cylinder 26 alsohas an inside diameter exceeding that of the roll portion ll by saidpredetermined amount. The cylinder 2| is also disposed coaxially withthe cylinders 20 and I8.

Similarly, cylinders 22, 23 and 24, when superposed coaxially on thosealready mentioned, together with a second cylinder l8 for the upperneck, complete the flask. The cylinder 23, as shown, is actually a solidring of appropriate thickness but may be a flanged cylinder like thatshown at 2 I.

The flask sections may be secured together in any convenient way, as,for example, by clamps 25 and wedges 26. In certain cases the sectionsmay be divided longitudinally, as indicated by the unsectioned surfaceMe of the section 2|. It is thus possible to remove the flask portionswhen desired, either after complete cooling or when the casting hassolidified but has not completely cooled, if metallurgicalconsiderations demand such treatment. In the case of a deeply entrantsection, such as the cylinder 23, it will be nec-- essary to make thesame in parts or else to destroy it, in order to remove it from thecasting.

The mold cavity may be formed by sweeping in the customary manner. onthe other hand, all the cylinders may be divided along an axial planeand the cavity formed by the use of a pattern.

The mold may be bottom-poured in well known manner through an aperture21 and is provided with the usual riser 28 at the top.

the desired finished roll, the outline of which is 56 The cylinders 20,2!, 22, etc., constitute wall portions of the flask corresponding to theroll portionsli, l1 and M, respectively; the inside diameter of eachwall portion exceeding the diameter of the corresponding roll portion bysubstantially the same amount. The axial length of the wall portion 20,furthermore, exceeds the axial length of the roll portion l5 by abouttwice said amount. The axial length of the wall portion 2|, however, isless than the axial length of the roll portion H by about twice saidamount; Consequently, the thickness of the layer of molding materialwithin the flask defining the cavity II is substantially the same bothradially and longitudinally at all points. This means that, duringcooling of the molten metal, the loss of heat from all points on thesurface of the casting to adjacent points on the flask will occur atsubstantially the same rate, thereby effecting a substantially uniformcooling throughout the surface area of the roll. While the cylinders l8forming the bottom and top of the flask as illustrated have the properinside diameter to give the uniform thickness of molding sand adjacenttively low limits. At the same time, the cost of a flask according tothe invention is comparable to that of a flask heretofore employed andpresents no additional difllculties in use. It will be understood thatcylindrical flask wall portions having dimensions appropriate to thoseof the roll portions generally cast may be made available and combinedin various ways as may be necessary to produce a roll having bodyportions of the desired diameters.

Although I have illustrated and described but a. preferred embodiment ofthe invention, it will the roll necks, this is not so important as theuniform cooling of all portions of the roll body.

Figure 2 illustrates a mo'difled flask 30 which is split longitudinallyand comprises a body 3| and ends 32 secured to the body. Instead ofbeing composed of rings of various inside diameters according to thediameters of the roll portions l3 through I! as in the flask ill, thebody 3| of flask 30 is composed of a cylindrical wall having rings 33projecting inwardly therefrom adjacent the roll portions of smallerdiameter. The rings 33 and the portions of the flask body therebetweenconstitute mold wall portions of different diam: eters corresponding tothose afforded by the rings 20, II, 22, etc. of Figure 1.

The body and ends of flask 30 may be cast or fabricated. In either case,they may be provided with water jackets 34 and 35, in order to hastenthe cooling of the roll cast therein. Pipe con nections 36 supply waterto the jackets and it drains therefrom through outlet pipes 31. Thejackets may be provided with longitudinal separator webs 38 to insureproper distribution of the cooling water around the flask body and ends.If the rings 33 are made hollow, holes 39 in the wall of the flask bodypermit entry of cooling water thereinto. If the flask is made bycasting,

the rings 33 may be integral with the wall of the body portion.

It will be apparent'that a mold formed in flask 30 will have a wall ofsubstantially uniform thickness at all points, despite variations in thediameter of the roll in different portions thereof.

The advantage of the invention has already been indicated, viz., thefact that the cooling of the roll as cast takes place at substantiallythe same rate at all points on the surface thereof. This makes itpossible to control the metallurgical structure more precisely thanheretofore and to avoid under-cooling at some points and overcooling atothers.

In addition, the flask of my invention simplifles the problem ofsupporting the sand forming the mold, ,each flask section of smallerdiameter carrying a portion of the vertical height of the sand layer.The flask also permits the mold recesses to be shaped to an accuracywithin relahe recognized that changes in the details of the constructionmay be made without departing from the spirit of the invention or thescope of the appended claims.

I claim:

1. A mold for casting a ferrous rolling mill roll having a grooved body,comprising in combination, a metal flask, said flask having a pluralityof cylindrical wall sections connected together coaxially, said wallsections being of different internal diameters and forming asubstantially continuous metal internal surface the axial and radialconfiguration of which is generally similar to that of said groovedbody, said internal surface being in direct metallic contact with theexteriors of said respective wall sections so that the ambient aircontacting the said exteriors removes the heat conveyed by the metalliccontact from said internal surface, and a layer of molding material suchas sand covering said internal surface of said wall sections tosubstantially the same thickness, whereby substantially uniform coolingthroughout the surface area of 83.1% grooved body is obtained when saidroll is cas 2. A mold for casting a ferrous rolling mill roll having agrooved body, comprising in combination, a hollow cylindrical metalflask, a hollow annular ring axially spaced along the interior wall ofsaid flask in each position corresponding to a circumferential groove insaid roll and form- 'ingwith the remainder of said interior wall acontinuous metal surface in direct metallic contact with a cooling fluidadapted to be circulated through said hollow flask and ring or rings,said metal surface substantially conforming in configuration to theconfiguration of the roll to be cast and uniformly larger than saidconfiguration of said roll, and a layer of molding material such as sandcovering each portion of said metal surface to a substantially evendepth corresponding to the distance between said configurations, wherebysubstantially uniform cooling throughout the surface area of said rollis obtained when said roll is cast.

FRANK CORDES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 50,187 Totten Sept. 26, 1865.843,679 Johns Feb. 12, 1907 990,710 Crook Apr. 25, 1911 2,104,906Mueller et a1 Jan. 11, 1938 2,377,731 Walcher June 5, 1945

